CVE-2026-40323: SP1 is a zero‑knowledge virtual machine that proves the correct execution of programs compiled for the RISC-V

Routine

HIGH 7.5REMOTEUPGRADE

CVE-2026-40323 is a high-severity flaw (CVSS 7.5) affecting sp1. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

SP1 is a zero‑knowledge virtual machine that proves the correct execution of programs compiled for the RISC-V architecture. In versions 6.0.0 through 6.0.2, a soundness vulnerability in the SP1 V6 recursive shard verifier allows a malicious prover to construct a recursive proof from a shard proof that the native verifier would reject. Version 6.1.0 fixes the issue.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 91%)
CISA exploited list	No
Weakness	CWE-345, CWE-354
Published	2026-04-18
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: succinct

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-18 00:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

succinct sp1 UPGRADE

Affected: >= 6.0.0 and < 6.1.0

Fixed in: 6.1.0

Safe to downgrade to: a release before 6.0.0

1. Check installed version

apt-cache policy sp1 || rpm -q sp1 || sp1 --version

2. UPGRADE to 6.1.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade sp1

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade sp1

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 6.0.0 (Debian / Ubuntu)

apt-cache madison sp1 sudo apt install sp1=<VERSION_BEFORE_6.0.0> sudo apt-mark hold sp1

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list sp1 sudo dnf downgrade sp1-<VERSION_BEFORE_6.0.0> sudo dnf versionlock add sp1

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-40323?

sp1: upgrade to 6.1.0. Exact commands for each OS are on this page.

Is CVE-2026-40323 being exploited?

CVE-2026-40323 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-40323 affect?

CVE-2026-40323 affects sp1. Severity is high (CVSS 7.5). SP1 is a zero‑knowledge virtual machine that proves the correct execution of programs compiled for the RISC-V architecture. In versions 6.0.0 through 6.0.2, a soundness vulnerability in the SP1 V6 recursive shard verifier allows a malicious

How urgent is CVE-2026-40323?

Priority 34/100. High severity; Remotely exploitable, no login, no user action

References

← Back to latest CVEs